This is direct and depressing evidence of marginalization based on race in the ancient world.
Porphyry, Life of Plotinus
“Plotinus, who was a philosopher during my life time, seemed to be ashamed of the body he was in. Because of this state, he could not endure to speak about his race or his parents.* And he was so hostile to posing for a painter or sculptor that he used to say to his friend Amelios when he was asking him to have an image made of himself, “Isn’t enough that I have to bear the image which nature forced upon me without also having to give in to you and leave an image of this image, as if it were a work worthy of seeing?”
1. Πλωτῖνος ὁ καθ᾿ ἡμᾶς γεγονὼς φιλόσοφος ἐῴκει μὲν αἰσχυνομένῳ ὅτι ἐν σώματι εἴη. Ἀπὸ δὲ τῆς τοιαύτης διαθέσεως οὔτε περὶ τοῦ γένους αὐτοῦ διηγεῖσθαι ἠνείχετο οὔτε περὶ τῶν γονέων οὔτε περὶ τῆς πατρίδος.* Ζωγράφου δὲ ἀνασχέσθαι ἢ πλάστου τοσοῦτον ἀπηξίου ὥστε καὶ λέγειν πρὸς Ἀμέλιον δεόμενον εἰκόνα αὐτοῦ γενέσθαι ἐπιτρέψαι· οὐ γὰρ ἀρκεῖ φέρειν ὃ ἡ φύσις εἴδωλον ἡμῖν περιτέθεικεν, ἀλλὰ καὶ εἰδώλου εἴδωλον συγχωρεῖν αὐτὸν ἀξιοῦν πολυχρονιώτερον καταλιπεῖν ὡς δή τι τῶν ἀξιοθεάτων ἔργων;
*Plotinus was Egyptian, cf. Eunapius, Vitae Philosophorum 445: Πλωτῖνος ἦν ἐξ Αἰγύπτου φιλόσοφος.